An organic electroluminescent (EL) element (organic EL device and organic EL machine) using an organic substance can realize plane emission due to the specific wavelength by selection of an optimum organic material, and can emit light in a thin and solid form, and thus commercialization of thin large-area full-color displays, light source devices for electronic photograph, back light for liquid displays, light sources for biometrics authentication such as vein sensor, and lighting of plane emission, and the like become urgent. Furthermore, the quality developments such as material development, optimization of configuration, and increase in production process efficiency are progressing so as to achieve further cost reduction and improvement of reliability in order To enlarge the uses.
The organic EL element is a thin-film solid light-emitting element which is generally disposed, on a base substrate, with at least a first electrode, an organic functional layer (light-emitting layer) composed of multi-layered organic compounds, and a second electrode. Note that one of the first electrode and the second electrode constitutes an anode, and the other constitutes a cathode. In addition, the organic functional layer contains least one organic luminescent substance and is constituted of many organic compounds.
In the organic EL element having such a configuration, when a voltage is applied between the first electrode and the second electrode, a positive hole is injected from one of the electrodes (anode) to the light-emitting layer, and an electron is injected from the other electrode (cathode) to the light-emitting layer. In addition, the energy level of the organic luminescent substance is returned from the conductive band to the valence electron band by recombination of the positive hole and electron which are injected into the light-emitting layer in the light-emitting layer, and then an energy generated at that time is emitted as light from the light-emitting layer.
Recently, in the technical field of the organic EL element, there has been required the establishment of mass production technique in which integrated producing is performed by using a flexible transparent film substrate as a base and by supply from a roll, from the viewpoint of the requirements such as thinning, weight reduction, large sizing, improvement of productivity and impact resistance of the organic EL element panel. In formation of the organic EL element on the transparent film substrate, there has occurred the dark spot phenomenon in which oxygen and moisture which penetrate into the transparent film substrate or sealing substrate from the atmosphere with the lapse of time degrade electrodes and light-emitting materials, and then cause non-light emission. Accordingly, it is necessary to provide a gas barrier layer and an inorganic sealing layer, and furthermore to seal the surfaces and surroundings of the element by sticking the sealing substrate such as a metal foil through the use of a resin adhesive.
Furthermore, in the organic EL element, a flexible print circuit film (FPC) and the like is connected, by using an anisotropic conductive film (ACF) or the like, to a wiring led out from the first electrode and the second electrode to the outside of the sealing substrate caused to adhere by the resin adhesive. In the connection, a heat pressure-bonding process at 100 to 200° C. is required. Accordingly, it is necessary to prevent the adhesive used in the heat pressure-bonding process from protruding at the metal wiring and the ACF crimped portion. Furthermore, since the metal disposed on the sealing substrate for obtaining moistureproofness and heat releasing property is electrically conductive, electrical short-circuiting and leakage occur to thereby generate light emission failure, when the metal wiring and apart of the end portion of the metal make contact with each other.
With respect to the problem, there has been a proposal that, in the configuration in which the sealing substrate is bonded together via a sheet-like sealing member, the protrusion of the sheet-like sealing member is prevented by disposition of a spacer and an adhesive layer at the terminal connection side (for example, see Patent Literature 1, Patent Literature 2) .